______ we are doing has never been done before.
| A．That | B．What |
| C．Which | D．Whether |
_____ is even more important is that as the earth cooled down, water began to appear on its surface.
| A．As | B．That | C．What | D．Where |
It was not immediately obvious _____ water was to be fundamental to the development of life.
| A．what | B．that | C．when | D．why |
-- I wonder if I could possibly use your car for tonight?
---______. I'm not using it anyhow.
| A．Sure, go head | B．I don't know | C．Yes, indeed | D．I don't care |
.--- Excuse me, can you tell me where the nearest bank is, please?
---______ Oh yes! It's past the office, next to a big market.
| A．Mm, let me think. | B．Oh, I beg your pardon? |
| C．You're welcome. | D．What do you mean? |
_________I saw her, I was amazed with her good behavior.
| A．The first time | B．For the first time |
| C．At first time | D．In time of |